The present invention relates to flow guide elements such as the ones used in various fields of natural science and technology. These flow guide elements are used as a part of flow guide systems which are used to guide flowing fluid media, especially gases or liquids over a specified path, for instance, to supply gases to a process or drain off exhaust gases from this process.
One important field of application of a flow guide is motor vehicle technology, and within that field, especially the area of guiding gaseous media. A first important example in the field of motor vehicle technology is the area of air guidance in connection with air filters in the intake tract of internal combustion engines. The air taken in, in this instance, has to be guided from the air filter to the internal combustion engine by using several partially straight, partially curved pieces of tubing.
A second example, in which flow guide elements are important, is air mass meters such as may also be used in the intake tract of internal combustion engine, for example. One important measuring principle is the so-called hot-film air mass meter, like the one described in German Patent Application No. DE 102 53 970, for example. In such devices, which may be inserted as plug-in sensors into the intake tract, for example, a part of the air is guided through a so-called bypass channel, which is curved several times, to a sensor chip on which the air mass throughput may be determined, using heating elements and temperature sensors. German Patent Application No. DE 102 53 970, for instance, describes the method of functioning of such hot-film air mass meters.
Depending on the field of application, such flow guide elements or systems, which are composed of these elements, are subject to various requirements. Thus, in the intake tract, especially in the area of the air filters, besides an intake air quantity that is stable in time and as free from fluctuations as possible, a high air throughput is of decisive importance. In other systems, by contrast, such as the hot-film air mass meters mentioned, the emphasis of requirements (besides as high a throughput as possible, which is subject to a signal level swing) is especially on high stability of the flow of the fluid medium.
In order to do justice to these requirements, even today, in many flow systems, especially in air flow systems, guide blades are used in order to divert the flow in as lossfree a manner as possible, and without flow separation. Such guide blades are used under various designations, and are also designated as auxiliary wings or sheet metal diverters.
One example of such guide blades is described in German Patent Application No. DE 102 53 970. In the system described there, in order to improve the flow conditions in the bypass channel of the hot-film air mass meter, a guide blade is proposed (there designated by reference numeral 50), which guides the flow and counteracts flow separation of the flow of the partial media flow from the channel walls of the measuring channel. Other examples may be found in the constructions of many current motor vehicle air filters.
An important disadvantage of this design approach is that the geometry and the position of the guide blades has to be adapted very carefully to be effective. Unfortunately, this constructive adaptation is not always possible, since the flow topology in air guidance systems frequently changes rapidly with flow speed. In this case it may happen that the guide blades or sheet metal baffles themselves cause additional separations and interferences.